Grain drying



Jan. 11, 1966 Original Filed April 15. 1960 J- S. WRIGHT GRAIN DRYING 4Sheets-Sheet 1 J] D D h H 7 l 50 k i\ 29 25 27 Fig- J. S. WRIGHT Jan.11, 1966 GRAIN DRYING 4 Sheets-Sheet 2 Original Filed April 15, 1960Jan. 11, 1966 J. s. WRIGHT 3,228,668

GRAIN DRYING Original Filed April 15, 1960 4 Sheets-Sheet 5 Jan. 11,1966 J. 5. WRIGHT 3,228,668

GRAIN DRYING Original Filed April 15, 1960 4 Sheets-Sheet 4 53 @TIMERFig.5

United States Patent 3,228,668 GRAIN DRYING John 5. Wright, Carleton,Mich, assignor, by mesne assignments, to General Precision, Inc,Tarrytown, N.Y., a corporation of Deiaware Original application Apr. 15,1960, Ser. No. 22,596, now Patent No. 3,152,873, dated Oct. 13, 1964.Divided and this application Dec. 27, 1963, Ser. No. 347,324 8 Claims.(Cl. 263-6) This is a division of copending application Serial No.22,596, filed April 15, 1960, now US. Patent No. 3,152,873.

This invention relates to the drying of grain and particularly to anapparatus for drying grain to a predetermined controllable moisturecontent.

The moisture content is an important characteristic of grain. In certainuses of grain, such as corn, it is essential that the moisture contentbe at a predetermined low level. Accordingly, it has been customary forthe price of grain to be related to the moisture content of the grain.Thus, when a farmer sells his grain to a grain elevator, he is paid apremium if the grain is of a predetermined low moisture content and ispaid a lesser amount and thereby is penalized, if the grain has a highmoisture content. There has therefore been a great need for aninexpensive method and apparatus for reducing the moisture content ofgrain to a predetermined low level.

Attempts to provide a low cost dryer have proved unsuccessful because ofthe high cost necessary in producing such apparatus and, in addition,the slow ineflicient operation of such dryers. A majority of such dryersutilized heated air which is passed over or through a batch of grain toreduce its moisture. The control of such heated air is very difficultand it is almost impossible to reduce the moisture of grain to apredetermined level. Thus, it has been customary in the use of suchdryers to heat the batch of grain one or more times, stop the dryer, andcheck the moisture content. The dryer is then started again to furtherheat the grain, if needed, in an effort to reduce the moisture contentof the grain to the vicinity of the desired percentage of moisture.

A major disadvantage of prior art grain dryers utilizing heated air hasbeen that such grain dryers tend to scorch or adversely affect thecomposition of the grain such as the starch content, germination,protein and carbohydrate content. Because such prior art methods heatfrom the exterior toward the interior, the accurate control of moisturecontent is very difiicult because the grain must reach an equillibriumwith the atmosphere after being heated.

Another very important disadvaintage of such dryers is the high costwhich makes it almost prohibitive for the average farmer to own andoperate such a dryer.

Accordingly, farmers have had to be content with obtaining whateverprice they could from the grain without making any particular efrort tocontrol the moisture content thereof. The problem of humidity controland drying of grain has become even more acute because of the recentadvent of other apparatus for handling grain such as picker shellers andthe like which make it possible for a farmer to convert his agriculturalproducts into grain form at low cost and at high rates. Without somemeans of controlling moisture content of the grain, the most efiicientuse of such apparatus is not achieved.

It is therefore an object of this invention to provide a novel apparatusfor reducing the moisture content of grain to a predetermined accuratecontrollable level.

It is a further object of the invention to provide novel apparatus forutilizing infrared gas heat in an enclosed space.

It is a further object of the invention to provide such an apparatuswherein the moisture content is reduced to a predetermined level quicklyand in a single pass.

It is a further object of the invention to provide novel apparatus fordrying grain wherein the germination and the composition of the grain isnot adversely affected by the drying.

It is a further object of the invention to provide such an apparatuswherein the grain is handled continuously.

It is a further object of the invention to provide such an aparatuswhich includes novel means for controlling the moisture content of thegrain.

It is a further object of the invention to provide such an apparatuswhich utilizes infrared gas heat.

In the drawings:

FIG. 1 is a perspective view of the apparatus embodying the inventionshowing the apparatus in operating position adjacent a truck.

FIG. 2 is a side elevation of the grain drying apparatus opposite thatshown in FIG. 1, parts being broken away.

FIG. 3 is a perspective view, parts being broken away, of an infraredgenerator assembly used in the gas drying apparatus.

FIG. 4 is a fragmentary top plan view of the assembly shown in FIG. 3.

FIG. 5 is a fragmentary rear perspective view of the apparatus shown inFIG. 3.

FIG. 6 is a longitudinal sectional view through an infrared generatorused in the assembly shown in FIGS. 3 to 5.

FIG. 7 is a fragmentary part sectional plan view taken generally alongline 77 in FIG. 1, parts being broken away.

FIG. 8 is a diagrammatic wiring diagram of a control apparatus for theinfrared generator apparatus.

FIG. 9 is a diagrammatic wiring diagram of a modified control apparatusfor the infrared generator apparatus.

Referring to FIG. 1, grain dryer 2% comprises a housing 21 which definesa tunnel to one end 22 of which grain is continuously fed by hand or bya conveyor, not shown. The grain is carried through the tunnel beneathinfrared generator assemblies 23 to the other end 24 thereof andthereafter is carried through a cooler 25 Where the temperature of thegrain is reduced so that the grain can finally be removed by a portablescrew conveyor 26 and loaded into a trailer or truck 27. As shown inFIG. 2, the grain dryer 20 is in the form of a trailer having wheels 28and a yoke 29 whereby it can be attached to a motor vehicle for movementfrom one place to the other. A retractable support 30 on yoke 29 holdsthe end of the grain dryer 20 in spaced relation to the ground when thegrain dryer is detached from the motor vehicle.

As the grain passes through the tunnel formed by the housing 21, it issubjected to infrared rays from the infrared generator assemblies 23which include gas generators that discharge infrared rays.

Infrared generator assemblies Referring to FIGS. 36, each infraredgenerator assembly 26 comprises a bank of infrared gas generators 31 3which burn a mixture of air and natural or liquid gas, such as the typeshown in the patent to Schwank 2,775,294 issued December 25, 1956. Suchinfrared generators comprise a housing 32 having a gas inlet 33 at oneend thereof. Gas enters the inlet 33 and is metered through an orifice34 to a chamber 35 which communicates with air from the exterior. Thegas is directed from the orifice 34 through the chamber 35 to the inletof a venturi 36 thereby aspirating air through the chamber 35 into theventuri 36. The gas and air are mixed in the venturi 36 and the mixtureis evenly distributed to the chamber 37. A ceramic mat 38 which is ofsubstantially uniform thickness is provided adjacent chamber 37. Mat 38has a plurality of fine holes 39 therein so that the gas and air passthrough the holes and burn as a separate minute flame at each hole. Whenthe gases burn, the entire sur face of the ceramic 38 has itstemperature elevated. The

flame is substantially invisible. By this combustion process, farinfrared rays are generated as contrasted to near infrared rays such asare developed by electrical infrared bulbs. A major portion of theinfrared rays generated range from 1.5 to 6.0 microns in wave lengthwith the greatest output being approximately 2.5 microns.

Referring to FIG. 3, each infrared generator assembly 23 includes arectangular housing 40 extend-ing along one end of each generator 31 andcommunicating with the air passages 35 of each of the generators 31. Anair intake stack 41 extends upwardly from housing 40 through the roof ofthe housing 21 to the exterior (FIG. 1). In this fashion, air from theexterior is aspirated by the passage of gas to the generators 31. Asecond housing 42 which is generally U-shaped and rectangular in crosssection is provided around the other ends and sides of the bank ofgenerators 31 and includes openings 43 in the bottom wall thereof andopenings 44 in the side walls thereof adjacent the plane of generators31. The openings 43 permit the exhaust of the moisture from the grainupwardly into theinterior of the housing 42. Openings 44 permit theexhaust of combustion gases from the generators 31 to the interior ofhousing 42. A stack 45 extends upwardly from housing 42 through the topof housing 21 to exhaust the moisture and exhaust gases to the exteriorof the dryer (FIG. 1). A hood 55 surrounds the bank of generators 31beneath housings 41 and 42.

As shown in FIG. 4, a bimetallic spring 46 is positioned on the top wallof chamber 42 adjacent the exhaust conduit 45 and is adapted to operatea damper 47 in the conduit 45. The spring 46 vertically moves a rack 48which engages teeth 49 on the shaft 50 of the damper 47. A mercuryswitch 51 is mounted on the shaft 50 of damper 47. As the heat in thechamber 42 causes the spring 46 to expand, the shaft 50 is caused torotate moving the damper 47 to an open position corresponding to theexpansion of the spring. When the shaft 50 is rotated to fully openposition, the switch 51 is actuated to energize a solenoid ,53 (FIG.that controls the valve supplying gas under pressure to the generators31.

Referring to FIG. 8, which is a diagrammatic wiring diagram of thecontrol mechanism for the infrared gas generator assembly, the mercuryswitch 51 is in series with solenoid 53. The switch 51 is also inparallel with a double'facting switch 56 that has one set of contactsthereof normally closed and extending to an on-oif switch 57. The otherset of contacts of switch 56 is connected to a heater element 58 whichalso extends to the switch 57. In order to energize the infraredgenerators, the onoff switch 57 is closed and the double'acting switch56 is depressed actuating a time delay 59 that keeps the switch 56depressed. In the depressed position, the switch 56 closes the circuitto the heater elements 58, one heater being provided for each generator31. When the heater elements 58 ignite the gas, the hot gases act onbimetallic spring 46 to move the damper 47 until the mercury switch aing the solenoid valve 53 energized.

' interval of time as established by timer 61.

51 is closed. Thus, when the time delay stops and the switch 56 returnsto its initial. position, a circuit is maintained through the mercuryswitch 51 thereby maintain- In the event that imperfect combustionoccurs at any time and the temperature of the exhaust gases drops, themercury switch opens to de-energize solenoid 53 and close the gas valve.

A modified form of control mechanism for the infrared gas generatorassemblies is shown in FIG. 9 wherein gas valve 53 is in series with aplurality of heater elements 60, one for each gas generator 31, and atimer switch 61 and a switch 52. A solenoid valve is in parallel with aplurality of thermostatically operated switches 63. When the switch 52is closed, the igniter elements 60 are energized and held in energizedposition for a predetermined If proper ignition of the generators 31occurs, then the heat closes thermostatic switches 63 maintaining theenergization of solenoid 63 after the timer opens the switch therein toigniter elements 60. i V

By the use of the housing 40 and conduit 41, the air for generators 31is aspirated from the exterior of the tunnel formed in the dryer housing21 thereby preventing dust or other foreign matter from the grain fromentering the generators 31 and plugging the holes 39 of the ceramic mats38. This eliminates improper combustion in the generators due to thepresence of foreign particles. The accumulation of carbon monoxide byimproper combustion is thereby entirely eliminated.

If the weight of the should change because of a change in humidity ofthe incoming air or because of a very dry condition in the tunnel, theamount of air aspirated by the burners will change. However, thethermostatically controlled damper 47 will produce a proper balancebetween the airand the gas continuing the performance of the burner athigh efliciency.

The separate chamber formed by the housing 42 with the external conduits45 insures that the products of combustion will not collect in thevicinity of the generators 31 and thereby adversely affect thecombustion. Infrared gas generators are characterized by forming a filmof carbon dioxide between the flame and the article being heated ordried. Any unbalance in combustion will cause a loss in the formation ofthis film of carbon dioxide so that the generators becomea fire hazard.In case of drying grain, the accumulation of uncombusted gases such ascarbon monoxide in the tunnel formed by the housing 21 would produce apotential fire or explosion hazard. Accordingly, the use of thegenerator assemblies permits the infrared gas generators to be used inan enclosed space. At the same time that the, exhaust gases are removedthrough the housing 42 of each assembly, the moisture driven off fromthe grain is also removed so that no moisture will accumulate in thehousing 21.

Conveying means The grain is moved and tumbled beneath successivegenerator assemblies 23. As shown in FIG. 2, successive generatorassemblies 23 are positioned at decreasing heights above the grain as itis moved through the tunnel formed by the housing 21,.or to the left asshown in FIG. 2. The housing 21 includes a longitudinally extendingframe 60 comprising longitudinal members 61 and transverse members 62.Uprights 63 extend upwardly from the frame 60 to support/the generatorassemblies 23 and the panels that comprise the enclosed tunnel.

U-shaped sheet panels 65 provide supports for the grain and the grain ismoved longitudinally and tumbled in the housing 65 by a screw conveyor66. As shown in FIG. 7, the screw conveyor 66 comprises hubs 67rotatably mounted in each end of the frame 66 (one only being shown).Shaft 68 on hubs 67 at one end of the dryer extend into position wherethey can be driven. Wire rods 69 extend between pairs of hubs 67. Aspiral 70 is formed by arcuate or annular pieces of metal joinedsuccessively and is Welded to rods 69 to form the spiral which is openat its center. Tabs 71 are struck out from the periphery of spiral 70and extend generally axially and the rods 69 are positioned in thestruck out portions of the spiral and are welded thereto. In thisfashion, the screw conveyor 66 is of such a construction that the grainis moved longitudinally and simultaneously tumbled. The use of the rods69 eliminates the necessity for a solid shaft thereby preventing mashingor grinding of the grain as it is moved and tumbled.

As the grain leaves the end 23 of the conveyor, a transversely extendingscrew 75 moves the grain laterally to a conduit 76 that directs thegrain to a cooling apparatus '77.

Operation In operation, the infrared gas generators 31 are ignited andthereby give off far infrafred rays which are directed downwardly ontothe conveyors 66. Grain is continuously introduced at the inlet 22 andis conveyed through the dryer by rotation of the conveyors 66, the grainbeing simultaneously tumbled as it is moved through the dryer. The farinfrared rays passing downwardly from generators 31 onto the grain causea uniform heating of the grain. The moisture that is given oif isexhausted through the housing 42 and exhaust conduit 45. The formationof the conveyors 66 by the annular blades tied together by the tie rods69 causes the proper movement of the grain and tumbling of the grainwithout grinding or mashing thereof.

Since the far infrared rays penetrate the grain and cause a uniformheating thereof throughout, no excessive burning or scorching of thegrain occurs.

After the grain has been dried, it is then cooled in a cooler such ascooler 77.

The control of the drying in accordance with the relative humidity ofair in equilibrium with the grain results in an accurate and speedycontrol of the moisture content of the grain within predeterminedlimits.

The use of far infrared rays for drying prevents any scorching andresults in a uniform drying of the grain so that when the grain iscooled it will remain at the humidity to which it has been dried withoutabsorbing humidity from the atmosphere. In this fashion, the moisturecontent of the grain will not fluctuate excessively in accordance withatmospheric conditions.

The provision of the housings and associated structure on the infraredgas generators permits the generators to be used in enclosed spaceswithout adversely affecting the burning of the gases therein and withoutcausing a fire or explosion hazard. The control mechanism used inassociation with the infrared gas generators assemblies provides for aproper ratio of air to gas under all conditions. Finally, the controlmechanism permits the safe shut off in case of failure of combustion.

The invention has been used in the drying of grain and particularlycorn. It has been found that it is possible to control the moisturecontent of corn within one-half of one percent. The resultant corn isnot only uniformly dried to a predetermined moisture content but this isaccomplished without adversely affecting the germination or thecomposition such as the starch content, protein, carbohydrates, nitrogenand the like.

I claim:

1. An infrared gas generator assembly comprising at least one infraredgas generator of the aspirator type including a housing to which amixture of gas and air are supplied through an air inlet in saidhousing, a perforated plate in one wall of said housing, means defininga chamber adjacent the air inlet of said generator which communicateswith the air inlet, conduit means extending from said chamber to anexterior source of air, means defining a second chamber adjacent theperiphery of said generator, said second chamber having openings thereinpositioned adjacent the periphery of said perforated plate whereby theexhaust gases from adjacent the surface of said perforated plate entersaid second chamber, and conduit means extending from said secondchamber and adapted to be connected to an exterior exhaust area.

2. An infrared gas generator assembly comprising at least one infraredgas generator of the aspirator type including a housing to which amixture of gas and air are supplied through an air inlet in saidhousing, aperforated plate in one wall of said housing whichcommunicates with the air inlet, means defining a chamber adjacent theair inlet of said generator, conduit means extending from said chamberto an exterior source of air, means defininga second chamber adjacentthe periphery of said generator, said secondchamber having openingstherein adjacent the periphery of said perforated plate whereby theexhaust gases from adjacent the surface of said perforated plate entersaid second chamber, conduit means extending from said second chamberand adapted to be connected to an exterior exhaust area, and meansresponsive to the temperature of the exhaust gases for controlling thesupply of gas to said generator.

3. An infrared gas generator assembly comprising at least one infraredgas generator of the aspirator type including a housing to which amixture of gas and air are supplied through an air inlet in saidhousing, a perforated plate in one wall of said housing whichcommunicates with the air inlet, means defining a chamber adjacent theair inlet of said generator, conduit means extending from said chamberto an exterior source of air, means defining a second chamber adjacentthe periphery of said generator, said second chamber having openingstherein adjacent the periphery of said perforated plate whereby theexhaust gases from adjacent the surface of said perforated plate entersaid second chamber, conduit means extending from said second chamberand adapted to be connected to an exterior exhaust area, and meansresponsive to the temperature of the exhaust gases for controlling theair supplied to said generator.

4. An infrared gas generator assembly comprising at least one infraredgas generator of the aspirator type including a housing to which amixture of gas and air are supplied through an air inlet in saidhousing, a perforated plate in one wall of said housing whichcommunicates with the air inlet, means defining a chamber adjacent theair inlet of said generator, conduit means extending from said chamberto an exterior source of air, means defining a second chamber adjacentthe periphery of said generator, said second chamber having openingstherein positioned adjacent the periphery of said perforated platewhereby the exhaust gases from adjacent the surface of said perforatedplate enter said second chamber, conduit means extending from saidsecond chamber and adapted to be connected to an exterior exhaust area,means responsive to the temperature of the exhaust gases for controllingthe supply of gas to said generator, and means responsive to thetemperature of the exhaust gases for controlling the air supplied tosaid generator.

5. An infrared gas generator assembly comprising at least one infraredgas generator of the aspirator type including a housing to which amixture of gas and air are supplied through an air inlet in saidhousing, a perforated plate in one wall of said housing whichcommunicates With the air inlet, means defining a chamber adjacent theair inlet of said generator, conduit means extending from said chamberto an exterior source of air, means defining a second chamber adjacentthe periphery of said generator, said second chamber having openingstherein adjacent the periphery of said perforated plate whereby theexhaust gases from adjacent the surface of said perforated plate entersaid plate, conduit means extending from said second chamber and adaptedto be connected to an exterior exhaust area, means for controlling theflow of gas to said generator, a temperature responsive elementpositioned in said second chamber, and means interconnecting saidtemperature responsive element to said valve means for controlling theflow of gas to said generator whereby when 7 1 the temperature of the,exhaust gases is below a predetermined level, said valve is closed andwhen the temperature of the exhaust gases is above the predeterminedlevel the gas valve is open.

6. The combination set forth in claim 5 including means for bypassingsaid temperature responsive element during ignition of said generator.

7. The combination set forth in claim 6 wherein said latter meansincludes a timed delay mechanism operative to return the means forcontrolling the flow of gas to the control of said temperatureresponsive element after a predetermined period of time. 1

8. The generator assembly as recited in claim 1, including meansdefining an enclosed tunnel with said generator assembly positioned inthe upper portionthereof, 1

and conveyor means for moving grain continuously References Cited by theExaminer UNITED STATES PATENTS 2,220,928 11/1940 Kienle eta1. 34 42,657,744 11/1953 Newton V15896 FOREIGN PATENTS 213,365 2/1958Australia.

WI'LLLAM F. ODEA, Primary Examiner JOHN J CAMBY, Examiner,

1. AN INFRARED GAS GENERATOR ASSEMBLY COMPRISING AT LEAST ONE INFRAREDGAS GENERATOR OF THE ASPIRATOR TYPE INCLUDING A HOUSING TO WHICH AMIXTURE OF GAS AND AIR ARE SUPPLIED THROUGH AN AIR INLET IN SAIDHOUSING, A PERFORATED PLATE IN ONE WALL OF SAID HOUSING, MEANS DEFININGA CHAMBER ADJACENT THE AIR INLET OF SAID GENERATOR WHICH COMMUNICATESWITH THE AIR INLET, CONDUIT MEANS EXTENDING FROM SAID CHAMBER TO ANEXTERIOR SOURCE OF AIR, MEANS DEFINING A SECOND CHAMBER ADJACENT THEPERIPHERY OF SAID GENERATOR, SAID SECOND CHAMBER HAVING OPENINGS THEREINPOSITIONED ADJACENT THE PERIPHERY OF SAID PEFORATED PLATE WHEREBY THEEXHAUST GASES FROM ADJACENT THE SURFACE OF SAID PERFORATED PLATE ENTERSAID SECOND CHAMBER, AND CONDUIT MEANS ENTER SAID SECOND CHAMBER ANDADAPTED TO BE CONNECTED TO AN EXTERIOR EXHAUST AREA.